The present invention relates to a disk reproducing apparatus such as a disk drive or the like for recording (writing) and/or reproducing (reading) information by using a disk-like recording medium such as an optical disk or an optical magnetic disk or the like as an information recording medium.
Conventionally in general in an optical disk functioning as a disk-like recording medium, there are three kinds: a read-only type optical disk such as a CD (compact disk) and a CD-ROM, a write once type optical disk allowing writing once, and a rewritable type allowing writing again. In a disk drive for recording/reproducing information by using these optical disks as a information recording medium, an optical disk is mounted horizontally on a turn table attached to the rotation shaft of a spindle motor and is driven to rotate. On the other hand, an information recording surface of the optical disk is exposed to a laser beam or the like perpendicularly by using an objective lens of an optical pickup. While horizontally moving the objective lens radially outward from the center of the optical disk, information is recorded on the information recording surface or information recorded on the information recording surface is reproduced.
The optical disk has a disk substrate formed to take the shape of a disk by using a synthetic resin material such as polycarbonate, and a signal recording surface formed on one main surface of this disk substrate. On the signal recording surface of the optical disk, a thin film made of a metal material such as aluminum is formed as a reflective layer.
The optical disk having such a configuration is mounted on a disk drive having the optical pickup to record and/or reproduce an information signal. This disk drive has a disk loading mechanism for mounting an optical disk on a disk mounting portion, and a rotation operation mechanism for holding the mounted optical disk so as to be opposed to the optical pickup and for rotating and operating the optical disk. This rotation operation mechanism forms the disk mounting portion for mounting the optical disk thereon. The optical disk inserted into an exterior casing of the disk drive from its outside is carried by the disk loading mechanism and mounted on the disk mounting portion.
As this disk loading mechanism, a disk loading mechanism of a so-called slot-in type has been proposed. This disk loading mechanism of slot-in type has a mechanism for carrying an optical disk inserted from a slot formed in the exterior casing to the disk mounting portion along the main surface of this optical disk, actuating a positioning member to position the optical disk with respect to the disk mounting portion and mount the optical disk, and thereafter separating the positioning member from the optical disk.
According to means for carrying the optical disk from the outside to the disk mounting portion, the disk drive of this kind is broadly classified into two groups, i.e., a group using a tray system and a group using a roller system.
In the tray system, a member called a tray for mounting an optical disk horizontally is formed so as to be able to be put into and out of the exterior casing. By drawing the tray with the optical disk mounted horizontally thereon into the exterior casing, the optical disk is carried to a disk chucking position by the tray and chucked in a turn table forming a part of the rotation operation mechanism. In the roller system, the optical disk is pinched from both sides of the main surface by a pair of rollers. By rotating the rollers, the optical disk inserted from a slot of the front face of the apparatus is drawn into the apparatus.
In such a disk loading mechanism of the conventional disk reproducing apparatus, however, it was necessary to install the optical disk positioning member and the mechanism for moving the positioning member. Therefore, the conventional disk loading mechanism had a problem of complicating the apparatus configuration.
In the disk drive of the tray system, the mechanism becomes comparatively simple and the cost thereof is low. At the present time, therefore, this tray system is the mainstream. Since the tray member has a large thickness, however, the whole apparatus becomes large in size. In addition, since the tray projects outside the apparatus, a user always needs to secure the space for projection of the tray. Especially in the case where the apparatus is mounted on a computer, these facts caused dissatisfaction of the user.
In the roller system, power is required for each of the rotation of the roller and the chucking operation of the disk, resulting in a high cost of the apparatus. In addition, since the optical disk is carried by pinch friction of the rollers, problems concerning durability and reliability, such as malfunction and possibility of a bad effect caused on the information recording surface by flaws due to roller slip and so on, have been pointed out. Thus, strict quality control for components such as the rollers and so on was demanded.